Add `Style/RedundantFreeze` to remove redudant `.freeze`

Since Rails 6.0 will support Ruby 2.4.1 or higher
`# frozen_string_literal: true` magic comment is enough to make string object frozen.
This magic comment is enabled by `Style/FrozenStringLiteralComment` cop.

* Exclude these files not to auto correct false positive `Regexp#freeze`
 - 'actionpack/lib/action_dispatch/journey/router/utils.rb'
 - 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb'

It has been fixed by https://github.com/rubocop-hq/rubocop/pull/6333
Once the newer version of RuboCop released and available at Code Climate these exclude entries should be removed.

* Replace `String#freeze` with `String#-@` manually if explicit frozen string objects are required

 - 'actionpack/test/controller/test_case_test.rb'
 - 'activemodel/test/cases/type/string_test.rb'
 - 'activesupport/lib/active_support/core_ext/string/strip.rb'
 - 'activesupport/test/core_ext/string_ext_test.rb'
 - 'railties/test/generators/actions_test.rb'

4 files changed, 8 insertions, 8 deletions

diff --git a/railties/lib/rails/backtrace_cleaner.rb b/railties/lib/rails/backtrace_cleaner.rb
index b1e3c923b7..7c2eb1dc42 100644
--- a/railties/lib/rails/backtrace_cleaner.rb
+++ b/railties/lib/rails/backtrace_cleaner.rb
@@ -6,13 +6,13 @@ module Rails
   class BacktraceCleaner < ActiveSupport::BacktraceCleaner
     APP_DIRS_PATTERN = /^\/?(app|config|lib|test|\(\w*\))/
     RENDER_TEMPLATE_PATTERN = /:in `.*_\w+_{2,3}\d+_\d+'/
-    EMPTY_STRING = "".freeze
-    SLASH        = "/".freeze
-    DOT_SLASH    = "./".freeze
+    EMPTY_STRING = ""
+    SLASH        = "/"
+    DOT_SLASH    = "./"
 
     def initialize
       super
-      @root = "#{Rails.root}/".freeze
+      @root = "#{Rails.root}/"
       add_filter { |line| line.sub(@root, EMPTY_STRING) }
       add_filter { |line| line.sub(RENDER_TEMPLATE_PATTERN, EMPTY_STRING) }
       add_filter { |line| line.sub(DOT_SLASH, SLASH) } # for tests
diff --git a/railties/lib/rails/commands/server/server_command.rb b/railties/lib/rails/commands/server/server_command.rb
index 9d517f3239..70789e0303 100644
--- a/railties/lib/rails/commands/server/server_command.rb
+++ b/railties/lib/rails/commands/server/server_command.rb
@@ -109,7 +109,7 @@ module Rails
       RACK_SERVERS = %w(cgi fastcgi webrick lsws scgi thin puma unicorn)
 
       DEFAULT_PORT = 3000
-      DEFAULT_PID_PATH = "tmp/pids/server.pid".freeze
+      DEFAULT_PID_PATH = "tmp/pids/server.pid"
 
       argument :using, optional: true
 
diff --git a/railties/test/generators/actions_test.rb b/railties/test/generators/actions_test.rb
index da52b6076a..6d53230eab 100644
--- a/railties/test/generators/actions_test.rb
+++ b/railties/test/generators/actions_test.rb
@@ -125,7 +125,7 @@ class ActionsTest < Rails::Generators::TestCase
   def test_gem_works_even_if_frozen_string_is_passed_as_argument
     run_generator
 
-    action :gem, "frozen_gem".freeze, "1.0.0".freeze
+    action :gem, -"frozen_gem", -"1.0.0"
 
     assert_file "Gemfile", /^gem 'frozen_gem', '1.0.0'$/
   end
diff --git a/railties/test/generators/resource_generator_test.rb b/railties/test/generators/resource_generator_test.rb
index 7a470d0d91..b99b4baf6b 100644
--- a/railties/test/generators/resource_generator_test.rb
+++ b/railties/test/generators/resource_generator_test.rb
@@ -65,7 +65,7 @@ class ResourceGeneratorTest < Rails::Generators::TestCase
   end
 
   def test_plural_names_are_singularized
-    content = run_generator ["accounts".freeze]
+    content = run_generator ["accounts"]
     assert_file "app/models/account.rb", /class Account < ApplicationRecord/
     assert_file "test/models/account_test.rb", /class AccountTest/
     assert_match(/\[WARNING\] The model name 'accounts' was recognized as a plural, using the singular 'account' instead\. Override with --force-plural or setup custom inflection rules for this noun before running the generator\./, content)
@@ -79,7 +79,7 @@ class ResourceGeneratorTest < Rails::Generators::TestCase
   end
 
   def test_mass_nouns_do_not_throw_warnings
-    content = run_generator ["sheep".freeze]
+    content = run_generator ["sheep"]
     assert_no_match(/\[WARNING\]/, content)
   end